Hydroxypyrimidine is generally produced in a three-stage reaction involving the formation of an imidate, amidine and the subsequent cyclization of the amidine to form the hydroxypyrimidine. Details of the prior processes used to prepare the hydroxypyrimidine are described in U.S. Pat. Nos. 4,014,879 and 5,231,180 and incorporated by their mention.
U.S. Pat. No. 4,014,879 describes a continuous ring closure process wherein the reaction is run in an aqueous sodium hydroxide solution using an excess of 20% to 30% of methyl-acetoacetate.
British Patent Number 2,083,814 runs in the reactions in a lower alkyl alcohol to cut down the excess of methyl-acetoacetate. However, yields of 90% or less were reported. Here, too, the reaction media was also water.